From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Date: Mon, 05 Aug 2013 21:02:12 +0000 Subject: Re: [PATCH] fbdev: suppress warning when assigning vga-save/restore base Message-Id: <520012D4.7020701@zytor.com> List-Id: References: <1375637141-2878-1-git-send-email-dh.herrmann@gmail.com> <51FE907A.2090201@zytor.com> <20130804.185146.1621476659301936865.davem@davemloft.net> <20130805202955.GH22789@localhost> In-Reply-To: <20130805202955.GH22789@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ondrej Zajicek Cc: David Miller , dh.herrmann@gmail.com, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, plagnioj@jcrosoft.com, tomi.valkeinen@ti.com, Ondrej Zary On 08/05/2013 01:29 PM, Ondrej Zajicek wrote: > > How this could even work? AFAIK these cards have to be explicitly programmed > to enable MMIO (which was not done in the patches). These patches claim that > it is for multi-domain PCI. I would guess that vgabase is NULL in common > configurations but if it is non-NULL, it probably wouldn't work, unless > there is some hardware magic that transparently converts MMIO (from CPU PoV) > to port IO (from card/PCI PoV). > They presumably use iowrite/ioread, which use either I/O instructions or memory instructions depending on the address. -hpa